Antistatic photographic materials



United States Patent 3,428,456 ANTISTATIC PHOTOGRAPHIC MATERIALS Herbert Grabhiifer, Cologne-Flittard, and Hans Ulrich,

Leverkusen, Germany, assignors to Agfa Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed June 2, 1965, Ser. No. 460,819 Claims priority, application Ggrmany, June 19, 1964,

US. Cl. 96--87 8 Claims Int. Cl. G03c 1/82; C07d 29/20 ABSTRACT OF THE DISCLOSURE This invention relates to an improved photographic element which contains antistatic agents, more particular which contains diesters of amidophosphoric acid with glycols or polyglycols which are etherified at one end.

It is known to add antistatic agents to, silver halide emulsion layers and/or auxiliary layers, such as protective or backing layers, of photographic materials in order to avoid electrostatic charging. A certain antistatic effect can be produced by means of the inorganic salts which already are present in the emulsions, such as sodium chloride, potassium bromide or sodium nitrate, all of which have a high electrical conductivity and are thus able to dissipate locally occurring electric charges. For the production and processing of photographic elements when using high casting speeds and severe drying conditions, the protective action obtained with these salts generally is insufficient. More effective substances are required to impart a lowest possible charging capacity to the film as well as -a high conductivity. Compounds which are known as antistatically effective substances and which are suitable for incorporation into photographic layers are aromatic, hydroaromatic or hetcrocyclic amines, quaternary ammonium salts, longchain aliphatic alcohols and acids, polyalkylene oxides, hexitol acetals and ketals, as well as sorbitol esters of higher fatty acids. However, difliculties arefrequently caused in the production of photographic elements by the prior known antistatic agents, such difliculties considerably restricting or even prohibiting the use thereof. Thus, reactions can occur with the wetting agents or casting additives present in the emulsion, this considerably impairing the casting operation. It is not possible to use the long-chain polyethylene oxides in a higher concentration for photographic layers, since they cause fogging and influence the development. Water-repellant substances with relatively long fatty residues are generally less compatible with the gelatine of the silver halide emulsion layers .or auxiliary layers. Other antistatic'agents with surface-active properties, which have a tendency to flocculate out, frequently cause small bubbles and streaks; antistatic 'agents containing acid groups are precipitated in certain pH ranges and are consequently not capable of unlimited use. The monofatty acid esters of sorbitol impart a greasy surface to the photographic material because of their water-repellant properties, which surface can only be written on with difficulty and leaves water stains when the layers are dried. Furthermore, structural changes frequently occur on the surface in the form of streaks or scale-like patterns, because of a non-uniform distribution or de-mixing of the added antistatic agents.

It is among the objects of the invention to provide antistatic agents which do not deleteriously affect the photographic properties of the photographic materials. The further object is to provide photographic materials with at least one light-sensitive silver halide emulsion layer which have improved antistatic properties.

The above objects have been attained by the use of diesters of amidophosphoric acid with glycols or polyglycols which are etherified at one end. The particular advantage of these compounds is that they are water-soluble, have good compatibility with gelatine and wetting agents and can be applied in all pH ranges. When added in relatively high concentration, they act as softeners and improve the mechanical properties of the film material.

Sluitable compounds include .those of the following formu a:

R and R represent hydrogen, alkyl, preferably having up to 12 carbon atoms, cycolalkyl, such as cyclohexyl, aryl, preferably a phenyl or a naphthyl, phenyl alkyl such as benzyl or phenyl ethyl or R :and R together can stand for the ring members, preferably methylene groups, necessary to complete a 5 or 6-membered heterocyclic ring,

R" represents alkyl, preferably with 12 to 20 carbon atoms, aryl, preferably a radial of the benzene series, more particular phenyl, which can be substituted with alkyl or olefinically unsaturated alkyl, preferably having between 1 and 20 carbon atoms, halogen, such as chloride and bromide, alkoxy groups having up to 12 carbon atoms and the like, which is substituted by an alkyl or alkylene radical with 1 to 12 carbon atoms,

A represents alkylene radicals with 2 to 4 carbon atoms, advantageously ethylene radicals, which can be partially replaced by propylene and/or butylene radicals,

n represents an integer from 1 to 40, advantageously 1 to The antistatic effect of the compounds of the present invention is unexpected because similar amido phosphoric acid esters with glycols or polyalkylene glycols with terminal 'hydroxy groups do not act as antistatic agents. For the present invention preferred compounds are etherified at the end of the alkylene glycol chain with a substituent containing a long-chained alkyl group having between 12 and 20 carbon atoms and with polyalkylene glycol chains containing between 6 and 12 alkylene glycol units.

The present antistatic agents are added to the photographic layers, more especially the protective layers for silver halide emulsion layers, advantageously in quantities from 1 to 25 percent by weight, calculated on the dry weight of binding agent of the layers, which binding agent is preferably gelatine.

To prepare the amidophosphoric acid esters, glycol ethers of the following general formula wherein R" and A have the above meaning are reacted according to common practice with an amidophosphoric acid dihalide or lower aliphatic ester in a molar ratio of about 2:1 in the presence of bases, such as pyridine. The amidophosphoric acid diahalides used for the aforesaid reaction can be substituted in the amide group by alkyl radicals, advantageously those with 1 to 6 carbon atoms, by aryl radicals, particularly phenyl radicals, which in their turn can be substituted by alkyl groups, alkoxy groups, phenoxy groups, halogen atoms or other substituents, or by aralkyl groups, such as benzyl. Furthermore, the nitrogen atom of the amide group can form part of a heterocyclic ring, e.g. piperidine or morpholine.

Special examples of suitable amidophosphoric acid dihalides or esters are those of the following formulae:

The above compounds are described in the article by A. Michaelis in Ann., volume 326, page 129 (1903).

The compounds indicated above are obtained as follows:

Compound I are obtained.

Compound II 23.7 g. of pyridine, 132 g. of p-nonylphenoxy decaethylene glycol and 19 g. of N,N-diethyl-phosphoric acid amide dichloride are reacted in accordance with the procedure 'given for Compound I. 124 g. of waxy compound of the are obtained.

Compound III 15.8 g. of pyridine, 23.2 g. of isononyloxy diethylene glycol and 9.5 g. of N,N-diethyl-phosphoric acid amide dichloride are reacted in accordance with the procedure 4 given for Compound I. 25 g. of a highly viscous substance are obtained.

Compound IV From 15.8 g. of pyridine, 59.8 g. of n-decyloxydecaethylene glycol and 11.2 g. of N-methyl-N-phenylphosphoric acid amide dichloride, and using the procedure indicated above, there are formed 62 g. of a brown coloured, semi-solid mass of the formula:

241 g. of the addition compound of 1 mol. of octylphenol, 10 mols of ethylene oxide and 10 mols of propylene oxide are mixed with 50 g. of pyridine and reacted in portions with 19 g. of N,N-diethyl-phosphoric acid amide dichloride. Working up takes place in a manner similar to Compound I. 210 g. of a substance are obtained which is pale brown in colour and has the theoretical formula 2 g. of the compounds indicated below are added to separate kilogram samples of a silver bromide emulsion which is ready for casting and which contains 6 percent of gelatine, and the solution is cast on to a suitable support of cellulose acetate or diethylene glycol terephthalate. After air-conditioning the film samples with 35 percent relative air humidity and at 20 C., the electrostatic charging in volts per cm. (v./cm.) is determined by means of the rotating field strength measuring instrument according to Schwenkhagen and the electric surface resistivity in ohms is determined with the Schneiden instrument.

Charging Surface Substance capacity resistivity (v./cm.) (10 9) Control specimen without additive +200 9.0 I +1 3. 5 +2. 5 8.0 +30 5. 0 +12 6. 5 +5 7. 5

Example 2 A protective layer containing 12 g. of gelatine per litre of casting solution was cast in a thickness of 1 mu onto gelatino-silver halide emulsion layer of a photographic material. In comparison tests, the protective layer solution ready for casting had 3 g. per litre of the compounds mentioned above added thereto and the casting was carried out in the same way. The following measurement results were obtained, using the test methods described above:

Surface resistivity 0) Charging capacity (v./cm.)

Substances IComparison specimen without additive macaw:

the formula wherein R and R taken alone each represent hydrogen, alkyl, cycloalkyl, phenyl, naphthyl and phenylalkyl; R and R together represent the ring members necessary to complete a heterocyclic ring having 5 to 6 ring members; R" stands for a member of the group consisting of alkyl and aryl; A represents alkylene radicals having between 2 to 4 carbon atoms and it stands for an integer from 1 to 40.

2. A light-sensitive photographic element containing at least one light-sensitive silver halide gelatin emulsion layer said photographic element having at least one layer containing an effective amount of an antistatic agent comprising a diester of amido-phosphoric acid having the formula wherein R and R when taken alone stand for hydrogen, alkyl having up to 12 carbon atoms, cycloalkyl, phenyl, naphthyL benzyl or phenyl ethyl,

R and R, together stand for the atoms necessary to complete a 5 or 6 membered ring R" stands for alkyl having from 12 to carbon atoms, phenyl or substituted products thereof wherein the substituents are saturated or unsaturated alkyl having up to 20 carbon atoms, halogen or alkoxy having up 0 12 carbon atoms,

A stands for alkylene having from 2 to 4 carbon atoms and n stands for an integer from 1 to 40,

3. A light-sentitive photographic element as defined in claim 2 wherein R stands for alkyl having from 12 to 20 carbon atoms and It stands for an integer between 6 and 12.

4. a light-sensitive photographic element as defined in claim 2 wherein the antistatic agent has the formula 5. A light-sensitive photographic element as defined in claim 2 wherein the antistatic agent has the formula 6. A light-sensitive photographic element as defined in claim 1 wherein the antistatic agent has the formula 7. A light-sensitive photographic element as defined in claim 1 wherein the antistatic agent has the formula 8. A light-sensitive photographic element as defined in claim 1 wherein the antistatic agent has the formula CH; C2H5 0 0(CH2-CH2OHCH2O 08H" n/ A 02115 0 CHz-CHz--OCHGHz-O -O H1-,

References Cited UNITED STATES PATENTS 3,264,108 8/1966 'Mackey et a1. 9685 NORMAN G. TORCHIN, Primary Examiner.

RONALD H. SMITH, Assistant Examiner.

US. Cl. X.R. 260-294.7 

